cern.colt.matrix.tdouble.impl
Class WrapperDoubleMatrix2D

java.lang.Object
  cern.colt.PersistentObject
      cern.colt.matrix.AbstractMatrix
          cern.colt.matrix.AbstractMatrix2D
              cern.colt.matrix.tdouble.DoubleMatrix2D
                  cern.colt.matrix.tdouble.impl.WrapperDoubleMatrix2D

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

DenseLargeDoubleMatrix2D, DiagonalDoubleMatrix2D, SparseCCDoubleMatrix2D, SparseCCMDoubleMatrix2D, SparseRCDoubleMatrix2D, SparseRCMDoubleMatrix2D

public class WrapperDoubleMatrix2D
extends DoubleMatrix2D

2-d matrix holding double elements; either a view wrapping another matrix or a matrix whose views are wrappers.

Version:

1.0, 04/14/2000

Author:

wolfgang.hoschek@cern.ch, Piotr Wendykier (piotr.wendykier@gmail.com)

See Also:

Serialized Form

Constructor Summary

WrapperDoubleMatrix2D(DoubleMatrix2D newContent)

Method Summary

DoubleMatrix2D	assign(double[] values) Sets all cells to the state specified by values.
DoubleMatrix2D	assign(DoubleMatrix2D y, DoubleDoubleFunction function) Assigns the result of a function to each cell; x[row,col] = function(x[row,col],y[row,col]).
DoubleMatrix2D	assign(float[] values) Sets all cells to the state specified by values.
void	dct2(boolean scale) Computes the 2D discrete cosine transform (DCT-II) of this matrix.
void	dctColumns(boolean scale) Computes the discrete cosine transform (DCT-II) of each column of this matrix.
void	dctRows(boolean scale) Computes the discrete cosine transform (DCT-II) of each row of this matrix.
void	dht2() Computes the 2D discrete Hartley transform (DHT) of this matrix.
void	dhtColumns() Computes the discrete Hertley transform (DHT) of each column of this matrix.
void	dhtRows() Computes the discrete Hertley transform (DHT) of each row of this matrix.
void	dst2(boolean scale) Computes the 2D discrete sine transform (DST-II) of this matrix.
void	dstColumns(boolean scale) Computes the discrete sine transform (DST-II) of each column of this matrix.
void	dstRows(boolean scale) Computes the discrete sine transform (DST-II) of each row of this matrix.
Object	elements() Returns the elements of this matrix.
boolean	equals(double value) Returns whether all cells are equal to the given value.
boolean	equals(Object obj) Compares this object against the specified object.
void	fft2() Computes the 2D discrete Fourier transform (DFT) of this matrix.
DenseLargeDComplexMatrix2D	getFft2() Returns new complex matrix which is the 2D discrete Fourier transform (DFT) of this matrix.
DenseLargeDComplexMatrix2D	getFftColumns() Returns new complex matrix which is the discrete Fourier transform (DFT) of each column of this matrix.
DenseLargeDComplexMatrix2D	getFftRows() Returns new complex matrix which is the discrete Fourier transform (DFT) of each row of this matrix.
DenseLargeDComplexMatrix2D	getIfft2(boolean scale) Returns new complex matrix which is the 2D inverse of the discrete Fourier transform (IDFT) of this matrix.
DenseLargeDComplexMatrix2D	getIfftColumns(boolean scale) Returns new complex matrix which is the inverse of the discrete Fourier transform (IDFT) of each column of this matrix.
DenseLargeDComplexMatrix2D	getIfftRows(boolean scale) Returns new complex matrix which is the inverse of the discrete Fourier transform (IDFT) of each row of this matrix.
double	getQuick(int row, int column) Returns the matrix cell value at coordinate [row,column].
void	idct2(boolean scale) Computes the 2D inverse of the discrete cosine transform (DCT-III) of this matrix.
void	idctColumns(boolean scale) Computes the inverse of the discrete cosine transform (DCT-III) of each column of this matrix.
void	idctRows(boolean scale) Computes the inverse of the discrete cosine transform (DCT-III) of each row of this matrix.
void	idht2(boolean scale) Computes the 2D inverse of the discrete Hartley transform (DHT) of this matrix.
void	idhtColumns(boolean scale) Computes the inverse of the discrete Hartley transform (DHT) of each column of this matrix.
void	idhtRows(boolean scale) Computes the inverse of the discrete Hartley transform (DHT) of each row of this matrix.
void	idst2(boolean scale) Computes the 2D inverse of the discrete size transform (DST-III) of this matrix.
void	idstColumns(boolean scale) Computes the inverse of the discrete sine transform (DST-III) of each column of this matrix.
void	idstRows(boolean scale) Computes the inverse of the discrete sine transform (DST-III) of each row of this matrix.
void	ifft2(boolean scale) Computes the 2D inverse of the discrete Fourier transform (IDFT) of this matrix.
DoubleMatrix2D	like(int rows, int columns) Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified number of rows and columns.
DoubleMatrix1D	like1D(int size) Construct and returns a new 1-d matrix of the corresponding dynamic type, entirelly independent of the receiver.
void	setQuick(int row, int column, double value) Sets the matrix cell at coordinate [row,column] to the specified value.
DoubleMatrix1D	vectorize() Returns a vector obtained by stacking the columns of the matrix on top of one another.
DoubleMatrix1D	viewColumn(int column) Constructs and returns a new slice view representing the rows of the given column.
DoubleMatrix2D	viewColumnFlip() Constructs and returns a new flip view along the column axis.
DoubleMatrix2D	viewDice() Constructs and returns a new dice (transposition) view; Swaps axes; example: 3 x 4 matrix --> 4 x 3 matrix.
DoubleMatrix2D	viewPart(int row, int column, int height, int width) Constructs and returns a new sub-range view that is a height x width sub matrix starting at [row,column].
DoubleMatrix1D	viewRow(int row) Constructs and returns a new slice view representing the columns of the given row.
DoubleMatrix2D	viewRowFlip() Constructs and returns a new flip view along the row axis.
DoubleMatrix2D	viewSelection(int[] rowIndexes, int[] columnIndexes) Constructs and returns a new selection view that is a matrix holding the indicated cells.
DoubleMatrix2D	viewStrides(int _rowStride, int _columnStride) Constructs and returns a new stride view which is a sub matrix consisting of every i-th cell.

Methods inherited from class cern.colt.matrix.tdouble.DoubleMatrix2D

aggregate, aggregate, aggregate, aggregate, assign, assign, assign, assign, assign, assign, assign, cardinality, copy, forEachNonZero, get, getMaxLocation, getMinLocation, getNegativeValues, getNonZeros, getPositiveValues, like, normalize, set, toArray, toString, viewSelection, viewSelection, viewSorted, zAssign8Neighbors, zMult, zMult, zMult, zMult, zSum

Methods inherited from class cern.colt.matrix.AbstractMatrix2D

checkShape, checkShape, columns, columnStride, index, rows, rowStride, size, toStringShort

Methods inherited from class cern.colt.matrix.AbstractMatrix

ensureCapacity, isView, trimToSize

Methods inherited from class cern.colt.PersistentObject

clone

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

WrapperDoubleMatrix2D

public WrapperDoubleMatrix2D(DoubleMatrix2D newContent)

Method Detail

assign

public DoubleMatrix2D assign(double[] values)

Description copied from class: DoubleMatrix2D

Sets all cells to the state specified by values. values is required to have the form values[row*column] and elements have to be stored in a row-wise order.

The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa.

Overrides:

assign in class DoubleMatrix2D

Parameters:

values - the values to be filled into the cells.

Returns:

this (for convenience only).

assign

public DoubleMatrix2D assign(float[] values)

Description copied from class: DoubleMatrix2D

Sets all cells to the state specified by values. values is required to have the form values[row*column] and elements have to be stored in a row-wise order.

The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa.

Overrides:

assign in class DoubleMatrix2D

Parameters:

values - the values to be filled into the cells.

Returns:

this (for convenience only).

assign

public DoubleMatrix2D assign(DoubleMatrix2D y,
                             DoubleDoubleFunction function)

Description copied from class: DoubleMatrix2D

Assigns the result of a function to each cell; x[row,col] = function(x[row,col],y[row,col]).

Example:

         // assign x[row,col] = x[row,col]<sup>y[row,col]</sup>
         m1 = 2 x 2 matrix 
         0 1 
         2 3
 
         m2 = 2 x 2 matrix 
         0 2 
         4 6
 
         m1.assign(m2, cern.jet.math.Functions.pow);
         -->
         m1 == 2 x 2 matrix
         1   1 
         16 729
 
 

For further examples, see the package doc.

Overrides:

assign in class DoubleMatrix2D

Parameters:

y - the secondary matrix to operate on.

function - a function object taking as first argument the current cell's value of this, and as second argument the current cell's value of y,

Returns:

this (for convenience only).

See Also:

DoubleFunctions

elements

public Object elements()

Description copied from class: DoubleMatrix2D

Returns the elements of this matrix.

Specified by:

elements in class DoubleMatrix2D

Returns:

the elements

getQuick

public double getQuick(int row,
                       int column)

Description copied from class: DoubleMatrix2D

Returns the matrix cell value at coordinate [row,column].

Provided with invalid parameters this method may return invalid objects without throwing any exception. You should only use this method when you are absolutely sure that the coordinate is within bounds. Precondition (unchecked): 0 <= column < columns() && 0 <= row < rows().

Specified by:

getQuick in class DoubleMatrix2D

Parameters:

row - the index of the row-coordinate.

column - the index of the column-coordinate.

Returns:

the value at the specified coordinate.

equals

public boolean equals(double value)

Description copied from class: DoubleMatrix2D

Returns whether all cells are equal to the given value.

Overrides:

equals in class DoubleMatrix2D

Parameters:

value - the value to test against.

Returns:

true if all cells are equal to the given value, false otherwise.

equals

public boolean equals(Object obj)

Description copied from class: DoubleMatrix2D

Compares this object against the specified object. The result is true if and only if the argument is not null and is at least a DoubleMatrix2D object that has the same number of columns and rows as the receiver and has exactly the same values at the same coordinates.

Overrides:

equals in class DoubleMatrix2D

Parameters:

obj - the object to compare with.

Returns:

true if the objects are the same; false otherwise.

like

public DoubleMatrix2D like(int rows,
                           int columns)

Description copied from class: DoubleMatrix2D

Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified number of rows and columns. For example, if the receiver is an instance of type DenseDoubleMatrix2D the new matrix must also be of type DenseDoubleMatrix2D, if the receiver is an instance of type SparseDoubleMatrix2D the new matrix must also be of type SparseDoubleMatrix2D, etc. In general, the new matrix should have internal parametrization as similar as possible.

Specified by:

like in class DoubleMatrix2D

Parameters:

rows - the number of rows the matrix shall have.

columns - the number of columns the matrix shall have.

Returns:

a new empty matrix of the same dynamic type.

like1D

public DoubleMatrix1D like1D(int size)

Description copied from class: DoubleMatrix2D

Construct and returns a new 1-d matrix of the corresponding dynamic type, entirelly independent of the receiver. For example, if the receiver is an instance of type DenseDoubleMatrix2D the new matrix must be of type DenseDoubleMatrix1D, if the receiver is an instance of type SparseDoubleMatrix2D the new matrix must be of type SparseDoubleMatrix1D, etc.

Specified by:

like1D in class DoubleMatrix2D

Parameters:

size - the number of cells the matrix shall have.

Returns:

a new matrix of the corresponding dynamic type.

dct2

public void dct2(boolean scale)

Computes the 2D discrete cosine transform (DCT-II) of this matrix.

Parameters:

scale - if true then scaling is performed

dctColumns

public void dctColumns(boolean scale)

Computes the discrete cosine transform (DCT-II) of each column of this matrix.

Parameters:

scale - if true then scaling is performed

dctRows

public void dctRows(boolean scale)

Computes the discrete cosine transform (DCT-II) of each row of this matrix.

Parameters:

scale - if true then scaling is performed

dst2

public void dst2(boolean scale)

Computes the 2D discrete sine transform (DST-II) of this matrix.

Parameters:

scale - if true then scaling is performed

dstColumns

public void dstColumns(boolean scale)

Computes the discrete sine transform (DST-II) of each column of this matrix.

Parameters:

scale - if true then scaling is performed

dstRows

public void dstRows(boolean scale)

Computes the discrete sine transform (DST-II) of each row of this matrix.

Parameters:

scale - if true then scaling is performed

dht2

public void dht2()

Computes the 2D discrete Hartley transform (DHT) of this matrix.

dhtColumns

public void dhtColumns()

Computes the discrete Hertley transform (DHT) of each column of this matrix.

dhtRows

public void dhtRows()

Computes the discrete Hertley transform (DHT) of each row of this matrix.

fft2

public void fft2()

Computes the 2D discrete Fourier transform (DFT) of this matrix. The physical layout of the output data is as follows:

 this[k1][2*k2] = Re[k1][k2] = Re[rows-k1][columns-k2], 
 this[k1][2*k2+1] = Im[k1][k2] = -Im[rows-k1][columns-k2], 
       0<k1<rows, 0<k2<columns/2, 
 this[0][2*k2] = Re[0][k2] = Re[0][columns-k2], 
 this[0][2*k2+1] = Im[0][k2] = -Im[0][columns-k2], 
       0<k2<columns/2, 
 this[k1][0] = Re[k1][0] = Re[rows-k1][0], 
 this[k1][1] = Im[k1][0] = -Im[rows-k1][0], 
 this[rows-k1][1] = Re[k1][columns/2] = Re[rows-k1][columns/2], 
 this[rows-k1][0] = -Im[k1][columns/2] = Im[rows-k1][columns/2], 
       0<k1<rows/2, 
 this[0][0] = Re[0][0], 
 this[0][1] = Re[0][columns/2], 
 this[rows/2][0] = Re[rows/2][0], 
 this[rows/2][1] = Re[rows/2][columns/2]
 

This method computes only half of the elements of the real transform. The other half satisfies the symmetry condition. If you want the full real forward transform, use getFft2. To get back the original data, use ifft2.

Throws:

IllegalArgumentException - if the row size or the column size of this matrix is not a power of 2 number.

getFft2

public DenseLargeDComplexMatrix2D getFft2()

Returns new complex matrix which is the 2D discrete Fourier transform (DFT) of this matrix.

Returns:

the 2D discrete Fourier transform (DFT) of this matrix.

getIfft2

public DenseLargeDComplexMatrix2D getIfft2(boolean scale)

Returns new complex matrix which is the 2D inverse of the discrete Fourier transform (IDFT) of this matrix.

Returns:

the 2D inverse of the discrete Fourier transform (IDFT) of this matrix.

getFftColumns

public DenseLargeDComplexMatrix2D getFftColumns()

Returns new complex matrix which is the discrete Fourier transform (DFT) of each column of this matrix.

Returns:

the discrete Fourier transform (DFT) of each column of this matrix.

getFftRows

public DenseLargeDComplexMatrix2D getFftRows()

Returns new complex matrix which is the discrete Fourier transform (DFT) of each row of this matrix.

Returns:

the discrete Fourier transform (DFT) of each row of this matrix.

getIfftColumns

public DenseLargeDComplexMatrix2D getIfftColumns(boolean scale)

Returns new complex matrix which is the inverse of the discrete Fourier transform (IDFT) of each column of this matrix.

Returns:

the inverse of the discrete Fourier transform (IDFT) of each column of this matrix.

getIfftRows

public DenseLargeDComplexMatrix2D getIfftRows(boolean scale)

Returns new complex matrix which is the inverse of the discrete Fourier transform (IDFT) of each row of this matrix.

Returns:

the inverse of the discrete Fourier transform (IDFT) of each row of this matrix.

idct2

public void idct2(boolean scale)

Computes the 2D inverse of the discrete cosine transform (DCT-III) of this matrix.

Parameters:

scale - if true then scaling is performed

idctColumns

public void idctColumns(boolean scale)

Computes the inverse of the discrete cosine transform (DCT-III) of each column of this matrix.

Parameters:

scale - if true then scaling is performed

idctRows

public void idctRows(boolean scale)

Computes the inverse of the discrete cosine transform (DCT-III) of each row of this matrix.

Parameters:

scale - if true then scaling is performed

idst2

public void idst2(boolean scale)

Computes the 2D inverse of the discrete size transform (DST-III) of this matrix.

Parameters:

scale - if true then scaling is performed

idstColumns

public void idstColumns(boolean scale)

Computes the inverse of the discrete sine transform (DST-III) of each column of this matrix.

Parameters:

scale - if true then scaling is performed

idstRows

public void idstRows(boolean scale)

Computes the inverse of the discrete sine transform (DST-III) of each row of this matrix.

Parameters:

scale - if true then scaling is performed

idht2

public void idht2(boolean scale)

Computes the 2D inverse of the discrete Hartley transform (DHT) of this matrix.

Parameters:

scale - if true then scaling is performed

idhtColumns

public void idhtColumns(boolean scale)

Computes the inverse of the discrete Hartley transform (DHT) of each column of this matrix.

Parameters:

scale - if true then scaling is performed

idhtRows

public void idhtRows(boolean scale)

Computes the inverse of the discrete Hartley transform (DHT) of each row of this matrix.

Parameters:

scale - if true then scaling is performed

ifft2

public void ifft2(boolean scale)

Computes the 2D inverse of the discrete Fourier transform (IDFT) of this matrix. The physical layout of the input data has to be as follows:

 this[k1][2*k2] = Re[k1][k2] = Re[rows-k1][columns-k2], 
 this[k1][2*k2+1] = Im[k1][k2] = -Im[rows-k1][columns-k2], 
       0<k1<rows, 0<k2<columns/2, 
 this[0][2*k2] = Re[0][k2] = Re[0][columns-k2], 
 this[0][2*k2+1] = Im[0][k2] = -Im[0][columns-k2], 
       0<k2<columns/2, 
 this[k1][0] = Re[k1][0] = Re[rows-k1][0], 
 this[k1][1] = Im[k1][0] = -Im[rows-k1][0], 
 this[rows-k1][1] = Re[k1][columns/2] = Re[rows-k1][columns/2], 
 this[rows-k1][0] = -Im[k1][columns/2] = Im[rows-k1][columns/2], 
       0<k1<rows/2, 
 this[0][0] = Re[0][0], 
 this[0][1] = Re[0][columns/2], 
 this[rows/2][0] = Re[rows/2][0], 
 this[rows/2][1] = Re[rows/2][columns/2]
 

This method computes only half of the elements of the real transform. The other half satisfies the symmetry condition. If you want the full real inverse transform, use getIfft2.

Parameters:

scale - if true then scaling is performed

Throws:

IllegalArgumentException - if the row size or the column size of this matrix is not a power of 2 number.

setQuick

public void setQuick(int row,
                     int column,
                     double value)

Description copied from class: DoubleMatrix2D

Sets the matrix cell at coordinate [row,column] to the specified value.

Provided with invalid parameters this method may access illegal indexes without throwing any exception. You should only use this method when you are absolutely sure that the coordinate is within bounds. Precondition (unchecked): 0 <= column < columns() && 0 <= row < rows().

Specified by:

setQuick in class DoubleMatrix2D

Parameters:

row - the index of the row-coordinate.

column - the index of the column-coordinate.

value - the value to be filled into the specified cell.

vectorize

public DoubleMatrix1D vectorize()

Description copied from class: DoubleMatrix2D

Returns a vector obtained by stacking the columns of the matrix on top of one another.

Specified by:

vectorize in class DoubleMatrix2D

Returns:

a vector of columns of this matrix.

viewColumn

public DoubleMatrix1D viewColumn(int column)

Description copied from class: DoubleMatrix2D

Constructs and returns a new slice view representing the rows of the given column. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa. To obtain a slice view on subranges, construct a sub-ranging view ( viewPart(...)), then apply this method to the sub-range view.

Example:

2 x 3 matrix: 1, 2, 3 4, 5, 6

viewColumn(0) ==>

Matrix1D of size 2: 1, 4

Overrides:

viewColumn in class DoubleMatrix2D

Parameters:

column - the column to fix.

Returns:

a new slice view.

See Also:

DoubleMatrix2D.viewRow(int)

viewColumnFlip

public DoubleMatrix2D viewColumnFlip()

Description copied from class: DoubleMatrix2D

Constructs and returns a new flip view along the column axis. What used to be column 0 is now column columns()-1, ..., what used to be column columns()-1 is now column 0. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa.

Example:

2 x 3 matrix: 1, 2, 3 4, 5, 6

columnFlip ==>

2 x 3 matrix: 3, 2, 1 6, 5, 4

columnFlip ==>

2 x 3 matrix: 1, 2, 3 4, 5, 6

Overrides:

viewColumnFlip in class DoubleMatrix2D

Returns:

a new flip view.

See Also:

DoubleMatrix2D.viewRowFlip()

viewDice

public DoubleMatrix2D viewDice()

Description copied from class: DoubleMatrix2D

Constructs and returns a new dice (transposition) view; Swaps axes; example: 3 x 4 matrix --> 4 x 3 matrix. The view has both dimensions exchanged; what used to be columns become rows, what used to be rows become columns. In other words: view.get(row,column)==this.get(column,row). This is a zero-copy transposition, taking O(1), i.e. constant time. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa. Use idioms like result = viewDice(A).copy() to generate an independent transposed matrix.

Example:

2 x 3 matrix: 1, 2, 3 4, 5, 6

transpose ==>

3 x 2 matrix: 1, 4 2, 5 3, 6

transpose ==>

2 x 3 matrix: 1, 2, 3 4, 5, 6

Overrides:

viewDice in class DoubleMatrix2D

Returns:

a new dice view.

viewPart

public DoubleMatrix2D viewPart(int row,
                               int column,
                               int height,
                               int width)

Description copied from class: DoubleMatrix2D

Constructs and returns a new sub-range view that is a height x width sub matrix starting at [row,column]. Operations on the returned view can only be applied to the restricted range. Any attempt to access coordinates not contained in the view will throw an IndexOutOfBoundsException.

Note that the view is really just a range restriction: The returned matrix is backed by this matrix, so changes in the returned matrix are reflected in this matrix, and vice-versa.

The view contains the cells from [row,column] to [row+height-1,column+width-1], all inclusive. and has view.rows() == height; view.columns() == width;. A view's legal coordinates are again zero based, as usual. In other words, legal coordinates of the view range from [0,0] to [view.rows()-1==height-1,view.columns()-1==width-1]. As usual, any attempt to access a cell at a coordinate column<0 || column>=view.columns() || row<0 || row>=view.rows() will throw an IndexOutOfBoundsException.

Overrides:

viewPart in class DoubleMatrix2D

Parameters:

row - The index of the row-coordinate.

column - The index of the column-coordinate.

height - The height of the box.

width - The width of the box.

Returns:

the new view.

viewRow

public DoubleMatrix1D viewRow(int row)

Description copied from class: DoubleMatrix2D

Constructs and returns a new slice view representing the columns of the given row. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa. To obtain a slice view on subranges, construct a sub-ranging view ( viewPart(...)), then apply this method to the sub-range view.

Example:

2 x 3 matrix: 1, 2, 3 4, 5, 6

viewRow(0) ==>

Matrix1D of size 3: 1, 2, 3

Overrides:

viewRow in class DoubleMatrix2D

Parameters:

row - the row to fix.

Returns:

a new slice view.

See Also:

DoubleMatrix2D.viewColumn(int)

viewRowFlip

public DoubleMatrix2D viewRowFlip()

Description copied from class: DoubleMatrix2D

Constructs and returns a new flip view along the row axis. What used to be row 0 is now row rows()-1, ..., what used to be row rows()-1 is now row 0. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa.

Example:

2 x 3 matrix: 1, 2, 3 4, 5, 6

rowFlip ==>

2 x 3 matrix: 4, 5, 6 1, 2, 3

rowFlip ==>

2 x 3 matrix: 1, 2, 3 4, 5, 6

Overrides:

viewRowFlip in class DoubleMatrix2D

Returns:

a new flip view.

See Also:

DoubleMatrix2D.viewColumnFlip()

viewSelection

public DoubleMatrix2D viewSelection(int[] rowIndexes,
                                    int[] columnIndexes)

Description copied from class: DoubleMatrix2D

Constructs and returns a new selection view that is a matrix holding the indicated cells. There holds view.rows() == rowIndexes.length, view.columns() == columnIndexes.length and view.get(i,j) == this.get(rowIndexes[i],columnIndexes[j]). Indexes can occur multiple times and can be in arbitrary order.

Example:

         this = 2 x 3 matrix:
         1, 2, 3
         4, 5, 6
         rowIndexes     = (0,1)
         columnIndexes  = (1,0,1,0)
         -->
         view = 2 x 4 matrix:
         2, 1, 2, 1
         5, 4, 5, 4
 
 

Note that modifying the index arguments after this call has returned has no effect on the view. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa.

To indicate "all" rows or "all columns", simply set the respective parameter

Overrides:

viewSelection in class DoubleMatrix2D

Parameters:

rowIndexes - The rows of the cells that shall be visible in the new view. To indicate that all rows shall be visible, simply set this parameter to null.

columnIndexes - The columns of the cells that shall be visible in the new view. To indicate that all columns shall be visible, simply set this parameter to null.

Returns:

the new view.

viewStrides

public DoubleMatrix2D viewStrides(int _rowStride,
                                  int _columnStride)

Description copied from class: DoubleMatrix2D

Constructs and returns a new stride view which is a sub matrix consisting of every i-th cell. More specifically, the view has this.rows()/rowStride rows and this.columns()/columnStride columns holding cells this.get(i*rowStride,j*columnStride) for all i = 0..rows()/rowStride - 1, j = 0..columns()/columnStride - 1. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa.

Overrides:

viewStrides in class DoubleMatrix2D

Parameters:

_rowStride - the row step factor.

_columnStride - the column step factor.

Returns:

a new view.